Optimization of natural dye extraction from the flowers of Ixora coccinea Linn. using response surface methodology

Present study optimized the extraction of natural dyes from Ixora coccinea Linn. (Rubiaceae) flowers to address the increasing environmental threats posed by using synthetic dyes. This method employed Box-Behnken design using response surface methodology to examine extraction factors like the extraction temperature (40-80 °C), extraction time (2-4 hr) and solvent-to-sample ratio (10-30 mL/g) to maximize the total monomeric anthocyanin content. The statistical analysis demonstrated that extraction temperature and solvent-to-sample ratio were the two main factors affecting the anthocyanin yield (p < 0.0001). The study showed a statistically strong validity with an adjusted R² of 0.9712 and a predicted R² of 0.9611, confirming excellent predictive ability. The optimal extraction conditions were set at 80 °C, 3 hr and 10 mL/g for maximum anthocyanin content of 66.67 mg c3gE/L. Gas Chromatography-Mass Spectroscopy studies of the ethanolic extract revealed a total of 38 phytochemical compounds including n-butyric acid 2-ethylhexyl ester (33.55 %), D-mannitol (25.01 %) and dl-?-tocopherol (18.02 %) being prominent. This study concludes successful optimization of extraction factors for I. coccinea flower dye and makes it a sustainable alternative over synthetic colorants having several industrial applications.